In disputable computing protocols such as BitVM and BitVMX, on-chain costs are largely determined by the efficiency of the underlying data signing scheme.

Existing implementations typically rely on Lamport or Winternitz signatures, which incur costs of 250–500 weight units per signed byte.

We introduce WISCH, a protocol that generates correlated sets of signatures across different signing schemes or messages. By exploiting this correlation, WISCH can serve as a drop-in replacement for existing schemes, reducing on-chain signing costs by at least 5× compared to Winternitz and 10× compared to Lamport and GC Wire labels.

The protocol is built on a clean separation between two components:

• On-chain verification core – designed so that costs depend only on the number of revealed items, not on the size of the entire message space.
• Off-chain preparation – where computational work takes place before verification, keeping blockchain operations efficient.

This architecture results in asymptotic efficiency: on-chain costs grow linearly with the number of openings and remain independent of the underlying domain, while the per-byte overhead decreases as message granularity increases.

Security is formally established through a simulation-based proof in the Universal Composability (UC) framework with an ideal ledger functionality. The proof relies on well-established assumptions for discrete-log-based signatures and hash-based commitments, within the algebraic group and global random-oracle models.

With these guarantees, WISCH provides succinct, verifiable on-chain checks along with strong, provable security, making it a powerful tool for scalable multiparty computation and privacy-preserving applications.

Access the full paper 🔗here to dive deeper into WISCH’s design, efficiency, and security guarantees.